A number of machines have been developed in the past for loading multi-tiered carts in a variety of different industries. Each industry has its own unique requirements, and therefore the cart loaders are generally designed so as to satisfy the requirements of the industry with which it is to be used. However, one requirement common to many industries is the need to load a plurality of objects, which are usually arranged in a plurality of rows and columns, onto each shelf of the cart. Therefore, not only must the loading machine perform the actual loading of the objects onto the shelves of the cart, but the machine must also arrange the objects into the plurality of rows and columns. A loading machine performing both of these tasks must do so in as little time as possible, in order to reduce the loading time of the cart, thus saving time and money.
U.S. Pat. No. 3,594,977 to Grasvoll discloses a loading machine in which objects to be loaded are supplied in a single column to a conveyor, which is then vertically raised until level with a plate, the single column then being pushed off of the conveyor and onto the plate. The conveyor is then lowered to receive another column, and then raised upward to the plate at which point the new column is again pushed off the conveyor and onto the plate, next to the first column. This process is repeated until the desired number of columns and rows are arranged on the plate. The machine also raises a multi-tiered cart until its lower shelf is level with the plate. The plate is then actuated forward until it is disposed within the cart, at which point a stripper plate is pivoted down and the plate actuated back to its original position, thus causing the objects to be left in the cart on the lower shelf The cart is then lowered to the next shelf, and the plate refilled with the columns and rows as before. A problem with this machine, however, is that it is complicated and expensive due to the large number of actuators, and the corresponding control system therefore, needed to move the various parts of the machine, including the conveyor, the plate, and the stripper plate. Further, since the conveyor must be moved up and down numerous times to obtain a full load of objects for each level of the cart, the machine is relatively slow, and is not able to load a cart as fast as would be desired.
Butterly, Jr. et al, U.S. Pat. No. 4,634,333, disclose a machine for loading containers of milk onto a multi-tiered cart. In this machine, the objects to be loaded are arranged onto a moving elevator, with the cart remaining stationary during loading. An actuator at each level of the cart is used to push the objects from the elevator and onto the cart. However, this machine utilizes a large number of actuators, in addition to a complicated mechanism for raising and lowering the elevator, resulting in a complicated and expensive machine. Further, as the elevator must be raised and lowered in order to place objects thereon, this increases the loading time of the cart.
An additional cart loading machine is disclosed by Robertson in U.S. Pat. No. 210,049, in which a multi-tiered cart is moved vertically as its different levels are filled from a platform. However, no mention is made of how the objects are moved from the platform and into the cart, nor how the objects are initially arranged on the platform.
U.S. Pat. No. 3,055,518 to Pearne et al discloses a machine in which each object is loaded one at a time at one level until the level is full, then the cart is moved to the next level to repeat the process. U.S. Pat. No. 4,697,974 to Eltoukhy; U.S. Pat. No. 4,824,310 to Kosmowski et al; and U.S. Pat. No. 5,595,468 to Wald teach machines which load and/or unload a single object for each level of the cart. These machines are not faced with the problem of arranging a plurality of objects prior to loading onto each level.
Therefore a need exists for a cart loading machine which is simple in construction and operation, and which is able to load a cart in a reduced amount of time.